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No. 16/July 14, 2000

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IN THIS ISSUE:
University of Illinois Off-Campus Courses, Fall 2000
The Off-Campus Graduate Studies (OCGS) program offered through the Department of Crop Sciences enables students to continue the

The Off-Campus Graduate Studies (OCGS) program offered through the Department of Crop Sciences enables students to continue their education at many locations in Illinois. Students who enroll in the program may choose to participate in courses primarily to advance their own professional development, or they may seek admission to the master's degree program in the Department of Crop Sciences.

Off-campus courses that are offered this fall include Principles of Plant Breeding, Weed Management in Agronomic Crops, Fundamentals of Insect Pest Management, Plant Physiology, Diseases of Field Crops, Crop Growth and Development, and Herbicide Fate and Mode of Action in Plants.



Reports of Extensive Corn Rootworm Larval Injury Common
On July 13, we will begin to evaluate our experimental plots for corn rootworm larval injury

On July 13, we will begin to evaluate our experimental plots for corn rootworm larval injury. On July 7, John Shaw found 8 corn rootworm pupae, 5 pre-pupae, 16 third-instar larvae, and 12 second-instar larvae. Pete Fandel, crop systems educator, Woodford County, observed significant corn rootworm injury in cornfields near Minonk (northeast Woodford County).

Reports such as Pete's are becoming more common as we approach mid-July. But don't automatically assume that a lodged field has significant corn rootworm larval injury. And if significant root pruning is discovered, don't panic. Many corn hybrids are able to regenerate roots from mid-July to mid-August, especially with the excellent soil moisture reserves we have in some areas of the state.



Grape Colaspis Adults Numerous in Soybean Fields
Soybean fields in many areas of Illinois continue to be "blessed" with bountiful densities of grape colaspis adults

Soybean fields in many areas of Illinois continue to be "blessed" with bountiful densities of grape colaspis adults. We should not be surprised by these observations based on the extensive number of reports concerning grape colaspis larval injury earlier this summer.

If you're using Pherocon AM traps to monitor densities of western corn rootworm adults in your soybean fields, it may be a good idea to also keep track of the numbers of grape colaspis adults that are caught; you will at least have some additional information to make a more informed management decision next spring.

 



Reports of White Grub Injury Still Trickling In
As odd as it seems, we are still receiving an occasional report of white grubs causing damage to crops, although it is not unus

As odd as it seems, we are still receiving an occasional report of white grubs causing damage to crops, although it is not unusual to find grubs in field crops during the summer. Note that the presence of white grubs in a field does not necessarily mean that the grubs are responsible for the injury. So bring your diagnostic skills to bear whenever you visit fields that just don't look right. A mistake in diagnosis could result in unnecessary or misplaced concern.

 



Flights for Second Generations of Corn Borers Are Under Way
Folks in southern counties may be in for a real struggle with southwestern corn borers this year

Folks in southern counties may be in for a real struggle with southwestern corn borers this year. On the other hand, European corn borers continue to be most noticeable by their relative absence. As the next few weeks unfold, we should get a better handle on the potential for infestations of the second generation of both of these pests. Scouting for the second generation of southwestern corn borers should intensify for at least 2 weeks after pollination is complete and should continue throughout July.

This article includes a list of insecticides that are labeled for use against the second generation of southwestern corn borer.



A Reminder About Several Insects in Corn Right Now
This article offers a few comments about several different insects that might be found in cornfields right now

This article offers a few comments about several different insects that might be found in cornfields right now. In addition to the corn rootworms, grape colaspis, southwestern corn borers, and European corn borers discussed in previous articles, you may encounter infestations (although none of them economic) of corn rootworm adults, Japanese beetles, grasshoppers, corn leaf aphids, and woollybear caterpillars. Corn rootworm adults, Japanese beetles, and woollybear caterpillars all clip silks, and grasshoppers and corn leaf aphids can also interfere with pollination and yield potential.

 



Watch for Late-Season Insect Problems
At this point in the growing season, things are progressing well

At this point in the growing season, things are progressing well. Disease and insect problems have been isolated. There may still be some concerns as the season progresses. The first potential problem is grasshoppers. Another is the southwestern corn borer. This article discusses treatments for these insects.



Phytophthora Rot on Soybean
Several reports of Phytophthora root rot on soybeans have been received from around the state

Several reports of Phytophthora root rot on soybeans have been received from around the state. The Phytophthora organism can cause disease symptoms on soybeans at any stage of growth. This article describes the symptoms of the disease.



Update on Fungal Leaf Blights
Common rust is developing in most cornfields around the state

Common rust is developing in most cornfields around the state. Eyespot is showing up on the upper leaves of corn plants in various areas around the state. Remember that what is important about all these leaf blights is not which blight you have but rather the percentage of leaf area blighted as a whole on the plant.



Considerations for Late-Season Soybean Herbicide Applications
Postemergence soybean herbicide applications are still being made to late-planted fields, double-crop soybeans, and fields need

Postemergence soybean herbicide applications are still being made to late-planted fields, double-crop soybeans, and fields needing a "cleanup" due to weed escapes. There are a number of considerations when choosing a postemergence herbicide for that final application.

This article discusses preharvest intervals and rotational crop intervals. Tables are provided that contain information regarding preharvest intervals and grazing restrictions for a number of postemergence soybean herbicides and rotational crop intervals for soybean herbicides.

 



More on Corn and Temperature
Conventional wisdom might say that when the weather is warm and humid, at least it's good weather for corn

Conventional wisdom might say that when the weather is warm and humid, at least it's good weather for corn. Although the belief that weather that's uncomfortably warm and humid is good for corn probably makes us feel a little better when we're having such weather, such conditions really are not ideal for corn growth and yield.

We usually associate humidity with how comfortable it is in the afternoon, but it's often more useful to consider the dewpoint, which is temperature at which the air is saturated. This article discusses the relationship between dewpoint and temperature and how they affect the corn crop.



Regional Reports
Extension center educators, unit educators, and unit assistants in northern, west-central, east-central, and southern Illinois

Extension center educators, unit educators, and unit assistants in northern, west-central, east-central, and southern Illinois prepare regional reports to provide more localized insight into pest situations and crop conditions in Illinois. The reports will keep you up to date on situations in field and forage crops as they develop throughout the season.

This week's issue includes reports from east-central Illinois, northern Illinois, southern Illinois, and west-central Illinois.





The Pest Management and Crop Development Bulletin
Executive Editor: Kevin Steffey, Extension Entomologist

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